-
Production, Quality Assurance and Quality Control of the SiPM Tiles for the DarkSide-20k Time Projection Chamber
Authors:
F. Acerbi,
P. Adhikari,
P. Agnes,
I. Ahmad,
S. Albergo,
I. F. Albuquerque,
T. Alexander,
A. K. Alton,
P. Amaudruz,
M. Angiolilli,
E. Aprile,
M. Atzori Corona,
D. J. Auty,
M. Ave,
I. C. Avetisov,
O. Azzolini,
H. O. Back,
Z. Balmforth,
A. Barrado Olmedo,
P. Barrillon,
G. Batignani,
P. Bhowmick,
M. Bloem,
S. Blua,
V. Bocci
, et al. (280 additional authors not shown)
Abstract:
The DarkSide-20k dark matter direct detection experiment will employ a 21 m^2 silicon photomultiplier (SiPM) array, instrumenting a dual-phase 50 tonnes liquid argon Time Projection Chamber (TPC). SiPMs are arranged into modular photosensors called Tiles, each integrating 24 SiPMs onto a printed circuit board (PCB) that provides signal amplification, power distribution, and a single-ended output f…
▽ More
The DarkSide-20k dark matter direct detection experiment will employ a 21 m^2 silicon photomultiplier (SiPM) array, instrumenting a dual-phase 50 tonnes liquid argon Time Projection Chamber (TPC). SiPMs are arranged into modular photosensors called Tiles, each integrating 24 SiPMs onto a printed circuit board (PCB) that provides signal amplification, power distribution, and a single-ended output for simplified readout. 16 Tiles are further grouped into Photo-Detector Units (PDUs). This paper details the production of the Tiles and the quality assurance and quality control (QA-QC) protocol established to ensure their performance and uniformity. The production and QA-QC of the Tiles are carried out at Nuova Officina Assergi (NOA), an ISO-6 clean room facility at LNGS. This process includes wafer-level cryogenic characterisation, precision flip-chip bonding, wire bonding, and extensive electrical and optical validation of each Tile. The overall production yield exceeds 83.5%, matching the requirements of the DarkSide-20k production plan. These results validate the robustness of the Tile design and its suitability for operation in a cryogenic environment.
△ Less
Submitted 9 July, 2025;
originally announced July 2025.
-
Flow and thermal modelling of the argon volume in the DarkSide-20k TPC
Authors:
DarkSide-20k Collaboration,
:,
F. Acerbi,
P. Adhikari,
P. Agnes,
I. Ahmad,
S. Albergo,
I. F. Albuquerque,
T. Alexander,
A. K. Alton,
P. Amaudruz,
M. Angiolilli,
E. Aprile,
M. Atzori Corona,
D. J. Auty,
M. Ave,
I. C. Avetisov,
O. Azzolini,
H. O. Back,
Z. Balmforth,
A. Barrado Olmedo,
P. Barrillon,
G. Batignani,
P. Bhowmick,
M. Bloem
, et al. (279 additional authors not shown)
Abstract:
The DarkSide-20k dark matter experiment, currently under construction at LNGS, features a dual-phase time projection chamber (TPC) with a ~50 t argon target from an underground well. At this scale, it is crucial to optimise the argon flow pattern for efficient target purification and for fast distribution of internal gaseous calibration sources with lifetimes of the order of hours. To this end, we…
▽ More
The DarkSide-20k dark matter experiment, currently under construction at LNGS, features a dual-phase time projection chamber (TPC) with a ~50 t argon target from an underground well. At this scale, it is crucial to optimise the argon flow pattern for efficient target purification and for fast distribution of internal gaseous calibration sources with lifetimes of the order of hours. To this end, we have performed computational fluid dynamics simulations and heat transfer calculations. The residence time distribution shows that the detector is well-mixed on time-scales of the turnover time (~40 d). Notably, simulations show that despite a two-order-of-magnitude difference between the turnover time and the half-life of $^{83\text{m}}$Kr of 1.83 h, source atoms have the highest probability to reach the centre of the TPC 13 min after their injection, allowing for a homogeneous distribution before undergoing radioactive decay. We further analyse the thermal aspects of dual-phase operation and define the requirements for the formation of a stable gas pocket on top of the liquid. We find a best-estimate value for the heat transfer rate at the liquid-gas interface of 62 W with an upper limit of 144 W and a minimum gas pocket inlet temperature of 89 K to avoid condensation on the acrylic anode. This study also informs the placement of liquid inlets and outlets in the TPC. The presented techniques are widely applicable to other large-scale, noble-liquid detectors.
△ Less
Submitted 26 June, 2025; v1 submitted 11 March, 2025;
originally announced March 2025.
-
Quality Assurance and Quality Control of the $26~\text{m}^2$ SiPM production for the DarkSide-20k dark matter experiment
Authors:
F. Acerbi,
P. Adhikari,
P. Agnes,
I. Ahmad,
S. Albergo,
I. F. Albuquerque,
T. Alexander,
A. K. Alton,
P. Amaudruz,
M. Angiolilli. E. Aprile,
M. Atzori Corona,
D. J. Auty,
M. Ave,
I. C. Avetisov,
O. Azzolini,
H. O. Back,
Z. Balmforth,
A. Barrado Olmedo,
P. Barrillon,
G. Batignani,
P. Bhowmick,
M. Bloem,
S. Blua,
V. Bocci,
W. Bonivento
, et al. (267 additional authors not shown)
Abstract:
DarkSide-20k is a novel liquid argon dark matter detector currently under construction at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) that will push the sensitivity for Weakly Interacting Massive Particle (WIMP) detection into the neutrino fog. The core of the apparatus is a dual-phase Time Projection Chamber (TPC), filled with \SI{50} {tonnes…
▽ More
DarkSide-20k is a novel liquid argon dark matter detector currently under construction at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) that will push the sensitivity for Weakly Interacting Massive Particle (WIMP) detection into the neutrino fog. The core of the apparatus is a dual-phase Time Projection Chamber (TPC), filled with \SI{50} {tonnes} of low radioactivity underground argon (UAr) acting as the WIMP target. NUV-HD-cryo Silicon Photomultipliers (SiPM)s designed by Fondazione Bruno Kessler (FBK) (Trento, Italy) were selected as the photon sensors covering two $10.5~\text{m}^2$ Optical Planes, one at each end of the TPC, and a total of $5~\text{m}^2$ photosensitive surface for the liquid argon veto detectors. This paper describes the Quality Assurance and Quality Control (QA/QC) plan and procedures accompanying the production of FBK~NUV-HD-cryo SiPM wafers manufactured by LFoundry s.r.l. (Avezzano, AQ, Italy). SiPM characteristics are measured at 77~K at the wafer level with a custom-designed probe station. As of March~2025, 1314 of the 1400 production wafers (94% of the total) for DarkSide-20k were tested. The wafer yield is $93.2\pm2.5$\%, which exceeds the 80\% specification defined in the original DarkSide-20k production plan.
△ Less
Submitted 19 March, 2025; v1 submitted 25 December, 2024;
originally announced December 2024.
-
Lifetimes of excited states in P-, As- and Sb-
Authors:
J. Karls,
M. Björkhage,
M. Blom,
N. D. Gibson,
O. Hemdal Lundgren,
M. Ji,
M. K. Kristiansson,
D. Leimbach,
J. E. Navarro Navarrete,
P. Reinhed,
A. Ringvall-Moberg,
S. Rosen,
H. T. Schmidt,
A. Simonsson,
D. Hanstorp
Abstract:
Radiative lifetimes of three elements of the nitrogen group have been experimentally investigated at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stockholm University. The experiments were performed through selective laser photodetachment of excited states of P$^-$, As$^-$ and Sb$^-$ ions stored in a cryogenic storage ring. The experimental results were compared with theoreti…
▽ More
Radiative lifetimes of three elements of the nitrogen group have been experimentally investigated at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stockholm University. The experiments were performed through selective laser photodetachment of excited states of P$^-$, As$^-$ and Sb$^-$ ions stored in a cryogenic storage ring. The experimental results were compared with theoretically predicted lifetimes, yielding a mixture of very good agreements in some cases and large discrepancies in others. These results are part of our efforts to map out the lifetimes of all excited states in negative ions. This data can be used to benchmark atomic theories, in particularly with respect to the degree of electron correlation that is incorporated in various theoretical models.
△ Less
Submitted 10 April, 2024;
originally announced April 2024.
-
The influence of impurities on the charge carrier mobility of small molecule organic semiconductors
Authors:
Pascal Friederich,
Artem Fediai,
Jing Li,
Anirban Mondal,
Naresh B. Kotadiya,
Franz Symalla,
Gert-Jan A. H. Wetzelaer,
Denis Andrienko,
Xavier Blase,
David Beljonne,
Paul W. M. Blom,
Jean-Luc Brédas,
Wolfgang Wenzel
Abstract:
Amorphous organic semiconductors based on small molecules and polymers are used in many applications, most prominently organic light emitting diodes (OLEDs) and organic solar cells. Impurities and charge traps are omnipresent in most currently available organic semiconductors and limit charge transport and thus device efficiency. The microscopic cause as well as the chemical nature of these traps…
▽ More
Amorphous organic semiconductors based on small molecules and polymers are used in many applications, most prominently organic light emitting diodes (OLEDs) and organic solar cells. Impurities and charge traps are omnipresent in most currently available organic semiconductors and limit charge transport and thus device efficiency. The microscopic cause as well as the chemical nature of these traps are presently not well understood. Using a multiscale model we characterize the influence of impurities on the density of states and charge transport in small-molecule amorphous organic semiconductors. We use the model to quantitatively describe the influence of water molecules and water-oxygen complexes on the electron and hole mobilities. These species are seen to impact the shape of the density of states and to act as explicit charge traps within the energy gap. Our results show that trap states introduced by molecular oxygen can be deep enough to limit the electron mobility in widely used materials.
△ Less
Submitted 8 November, 2020; v1 submitted 30 August, 2019;
originally announced August 2019.
-
Dianion diagnostics in DESIREE: High-sensitivity detection of $\text{C}_{n}^{2-}$ from a sputter ion source
Authors:
K. C. Chartkunchand,
M. H. Stockett,
E. K. Anderson,
G. Eklund,
M. K. Kristiansson,
M. Kamińska,
N. de Ruette,
M. Blom,
M. Björkhage,
A. Källberg,
P. Löfgren,
P. Reinhed,
S. Rosén,
A. Simonsson,
H. Zettergren,
H. T. Schmidt,
H. Cederquist
Abstract:
A sputter ion source with a solid graphite target has been used to produce dianions with a focus on carbon cluster dianions, $\text{C}_{n}^{2-}$, with $n=7-24$. Singly and doubly charged anions from the source were accelerated together to kinetic energies of 10 keV per atomic unit of charge and injected into one of the cryogenic (13 K) ion-beam storage rings of the Double ElectroStatic Ion Ring Ex…
▽ More
A sputter ion source with a solid graphite target has been used to produce dianions with a focus on carbon cluster dianions, $\text{C}_{n}^{2-}$, with $n=7-24$. Singly and doubly charged anions from the source were accelerated together to kinetic energies of 10 keV per atomic unit of charge and injected into one of the cryogenic (13 K) ion-beam storage rings of the Double ElectroStatic Ion Ring Experiment facility at Stockholm University. Spontaneous decay of internally hot $\text{C}_{n}^{2-}$ dianions injected into the ring yielded $\text{C}^{-}$ anions with kinetic energies of 20 keV, which were counted with a microchannel plate detector. Mass spectra produced by scanning the magnetic field of a $90^{\circ}$ analyzing magnet on the ion injection line reflect the production of internally hot $\text{C}_{7}^{2-}-\text{C}_{24}^{2-}$ dianions with lifetimes in the range of tens of microseconds to milliseconds. In spite of the high sensitivity of this method, no conclusive evidence of $\text{C}_{6}^{2-}$ was found while there was a clear $\text{C}_{7}^{2-}$ signal with the expect isotopic distribution. An upper limit is deduced for a $\text{C}_{6}^{2-}$ signal that is two orders-of-magnitue smaller than that for $\text{C}_{7}^{2-}$. In addition, $\text{C}_{n}\text{O}^{2-}$ and $\text{CsCu}^{2-}$ dianions were detected.
△ Less
Submitted 31 March, 2018;
originally announced April 2018.
-
Radiative lifetimes of the bound excited states of $\text{Pt}^{-}$
Authors:
K. C. Chartkunchand,
M. Kamińska,
E. K. Anderson,
M. K. Kristiansson,
G. Eklund,
O. M. Hole,
R. F. Nascimento,
M. Blom,
M. Björkhage,
A. Källberg,
P. Löfgren,
P. Reinhed,
S. Rosén,
A. Simonsson,
R. D. Thomas,
S. Mannervik,
V. T. Davis,
P. A. Neill,
J. S. Thompson,
D. Hanstorp,
H. Zettergren,
H. Cederquist,
H. T. Schmidt
Abstract:
The intrinsic radiative lifetimes of the $5d^{10}6s$ $^{2}\text{S}_{1/2}$ and $5d^{9}6s^{2}$ $^{2}\text{D}_{3/2}$ bound excited states in the platinum anion $\text{Pt}^{-}$ have been studied at cryogenic temperatures at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stockholm University. The intrinsic lifetime of the higher-lying $5d^{10}6s$ $^{2}\text{S}_{1/2}$ state was measu…
▽ More
The intrinsic radiative lifetimes of the $5d^{10}6s$ $^{2}\text{S}_{1/2}$ and $5d^{9}6s^{2}$ $^{2}\text{D}_{3/2}$ bound excited states in the platinum anion $\text{Pt}^{-}$ have been studied at cryogenic temperatures at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stockholm University. The intrinsic lifetime of the higher-lying $5d^{10}6s$ $^{2}\text{S}_{1/2}$ state was measurement to be 2.54$\pm$0.10 s, while only a lifetime in the range of 50 - 200 ms could be estimated for the $5d^{9}6s^{2}$ $^{2}\text{D}_{3/2}$ fine-structure level. The storage lifetime of the $\text{Pt}^{-}$ ion beam was measured to be a little over 15 minutes at a ring temperature of 13 K. The present study reports the lifetime of an atomic negative ion in an excited bound state with an electron configuration different from that of the ground state.
△ Less
Submitted 31 March, 2018;
originally announced April 2018.
-
First storage of ion beams in the Double Electrostatic Ion-Ring Experiment - DESIREE
Authors:
H. T. Schmidt,
R. D. Thomas,
M. Gatchell,
S. Rosén,
P. Reinhed,
P. Löfgren,
L. Brännholm,
M. Blom,
M. Björkhage,
E. Bäckström,
J. D. Alexander,
S. Leontein,
D. Hanstorp,
H. Zettergren,
L. Liljeby,
A. Källberg,
A. Simonsson,
F. Hellberg,
S. Mannervik,
M. Larsson,
W. D. Geppert,
K. G. Rensfelt,
H. Danared,
A. Paál,
M. Masuda
, et al. (9 additional authors not shown)
Abstract:
We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment; DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C$_n^-$, $n=1,2,3,4$) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For…
▽ More
We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment; DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C$_n^-$, $n=1,2,3,4$) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C$_2^-$ molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s $\pm$ 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10$^{-14}$ mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity. %The latter effect becomes insignificant after longer storage times of typically 100-150 seconds and we then observe a constant decay rate due to residual-gas collisions.
△ Less
Submitted 31 March, 2018;
originally announced April 2018.
-
Bright X-ray radiation from plasma bubbles in an evolving laser wakefield accelerator
Authors:
M. S. Bloom,
M. J. V. Streeter,
S. Kneip,
R. A. Bendoyro,
O. Cheklov,
J. M. Cole,
A. Doepp,
C. J. Hooker,
J. Holloway,
J. Jiang,
N. C. Lopes,
H. Nakamura,
P. A. Norreys,
P. P. Rajeev,
D. R. Symes,
J. Schreiber,
J. C. Wood,
M. Wing,
Z. Najmudin,
S. P. D. Mangles
Abstract:
We show that the properties of the electron beam and bright x-rays produced by a laser wakefield accelerator can be predicted if the distance over which the laser self-focuses and compresses prior to self-injection is taken into account. A model based on oscillations of the beam inside a plasma bubble shows that performance is optimised when the plasma length is matched to the laser depletion leng…
▽ More
We show that the properties of the electron beam and bright x-rays produced by a laser wakefield accelerator can be predicted if the distance over which the laser self-focuses and compresses prior to self-injection is taken into account. A model based on oscillations of the beam inside a plasma bubble shows that performance is optimised when the plasma length is matched to the laser depletion length. With a 200~TW laser pulse this results in an x-ray beam with median photon energy of \unit[20]{keV}, $> 6\times 10^{8}$ photons above \unit[1]{keV} per shot and a peak brightness of $\unit[3 \times 10^{22}]{photons~s^{-1}mrad^{-2}mm^{-2} (0.1\% BW)^{-1}}$.
△ Less
Submitted 6 May, 2020; v1 submitted 16 October, 2017;
originally announced October 2017.
-
Observation of Laser Power Amplification in a Self-Injecting Laser Wakefield Accelerator
Authors:
M. J. V. Streeter,
S. Kneip,
M. S. Bloom,
R. A. Bendoyro,
O. Chekhlov,
A. E. Dangor,
A. Döpp,
C. J. Hooker,
J. Holloway,
J. Jiang,
N. C. Lopes,
H. Nakamura,
P. A. Norreys,
C. A. J. Palmer,
P. P. Rajeev,
J. Schreiber,
D. R. Symes,
M. Wing,
S. P. D. Mangles,
Z. Najmudin
Abstract:
We report on the depletion and power amplification of the driving laser pulse in a strongly-driven laser wakefield accelerator. Simultaneous measurement of the transmitted pulse energy and temporal shape indicate an increase in peak power from $187 \pm 11$ TW to a maximum of $318 \pm 12$ TW after 13 mm of propagation in plasma density of $0.9 \times 10^{18}$ cm$^{-3}$. The power amplification is c…
▽ More
We report on the depletion and power amplification of the driving laser pulse in a strongly-driven laser wakefield accelerator. Simultaneous measurement of the transmitted pulse energy and temporal shape indicate an increase in peak power from $187 \pm 11$ TW to a maximum of $318 \pm 12$ TW after 13 mm of propagation in plasma density of $0.9 \times 10^{18}$ cm$^{-3}$. The power amplification is correlated with the injection and acceleration of electrons in the nonlinear wakefield. This process is modeled by including localized redshift and subsequent group delay dispersion at the laser pulse front.
△ Less
Submitted 21 June, 2018; v1 submitted 15 October, 2017;
originally announced October 2017.
-
The lifetime of the bound excited level in Ni$^-$
Authors:
M. Kamińska,
V. T. Davis,
O. M. Hole,
R. F. Nascimento,
K. C. Chartakunchand,
M. Blom,
M. Björkhage,
A. Källberg,
P. Löfgren,
P. Reinhed,
S. Rosén,
A. Simonsson,
R. D. Thomas,
S. Mannervik,
P. A. Neill,
J. S. Thompson,
H. T. Schmidt,
H. Cederquist,
D. Hanstorp
Abstract:
The intrinsic lifetime of the upper level in the bound-bound 3d$^9$4s$^2$ $^2$D$_{3/2}$ $\rightarrow$ 3d$^9$4s$^2$ $^2$D$_{5/2}$ radiative transition in Ni$^-$ was measured to be 15.1 $\pm$ 0.4 s. The experiment was performed at cryogenic temperatures in one of the ion-beam storage rings of the DESIREE (Double ElectroStatic Ion Ring Experiment) facility at Stockholm University. The storage lifetim…
▽ More
The intrinsic lifetime of the upper level in the bound-bound 3d$^9$4s$^2$ $^2$D$_{3/2}$ $\rightarrow$ 3d$^9$4s$^2$ $^2$D$_{5/2}$ radiative transition in Ni$^-$ was measured to be 15.1 $\pm$ 0.4 s. The experiment was performed at cryogenic temperatures in one of the ion-beam storage rings of the DESIREE (Double ElectroStatic Ion Ring Experiment) facility at Stockholm University. The storage lifetime of the Ni$^-$ ion-beam was measured to be close to five minutes at a ring temperature of 13 K.
△ Less
Submitted 2 December, 2015; v1 submitted 13 November, 2015;
originally announced November 2015.
-
Advanced Virgo: a 2nd generation interferometric gravitational wave detector
Authors:
F. Acernese,
M. Agathos,
K. Agatsuma,
D. Aisa,
N. Allemandou,
A. Allocca,
J. Amarni,
P. Astone,
G. Balestri,
G. Ballardin,
F. Barone,
J. -P. Baronick,
M. Barsuglia,
A. Basti,
F. Basti,
Th. S. Bauer,
V. Bavigadda,
M. Bejger,
M. G. Beker,
C. Belczynski,
D. Bersanetti,
A. Bertolini,
M. Bitossi,
M. A. Bizouard,
S. Bloemen
, et al. (209 additional authors not shown)
Abstract:
Advanced Virgo is the project to upgrade the Virgo interferometric detector of gravitational waves, with the aim of increasing the number of observable galaxies (and thus the detection rate) by three orders of magnitude. The project is now in an advanced construction phase and the assembly and integration will be completed by the end of 2015. Advanced Virgo will be part of a network with the two A…
▽ More
Advanced Virgo is the project to upgrade the Virgo interferometric detector of gravitational waves, with the aim of increasing the number of observable galaxies (and thus the detection rate) by three orders of magnitude. The project is now in an advanced construction phase and the assembly and integration will be completed by the end of 2015. Advanced Virgo will be part of a network with the two Advanced LIGO detectors in the US and GEO HF in Germany, with the goal of contributing to the early detections of gravitational waves and to opening a new observation window on the universe. In this paper we describe the main features of the Advanced Virgo detector and outline the status of the construction.
△ Less
Submitted 16 October, 2014; v1 submitted 18 August, 2014;
originally announced August 2014.
-
Reconstruction of the gravitational wave signal $h(t)$ during the Virgo science runs and independent validation with a photon calibrator
Authors:
Virgo collaboration,
T. Accadia,
F. Acernese,
M. Agathos,
A. Allocca,
P. Astone,
G. Ballardin,
F. Barone,
M. Barsuglia,
A. Basti,
Th. S. Bauer,
M. Bejger,
M . G. Beker,
C. Belczynski,
D. Bersanetti,
A. Bertolini,
M. Bitossi,
M. A. Bizouard,
M. Blom,
M. Boer,
F. Bondu,
L. Bonelli,
R. Bonnand,
V. Boschi,
L. Bosi
, et al. (171 additional authors not shown)
Abstract:
The Virgo detector is a kilometer-scale interferometer for gravitational wave detection located near Pisa (Italy). About 13 months of data were accumulated during four science runs (VSR1, VSR2, VSR3 and VSR4) between May 2007 and September 2011, with increasing sensitivity.
In this paper, the method used to reconstruct, in the range 10 Hz-10 kHz, the gravitational wave strain time series $h(t)$…
▽ More
The Virgo detector is a kilometer-scale interferometer for gravitational wave detection located near Pisa (Italy). About 13 months of data were accumulated during four science runs (VSR1, VSR2, VSR3 and VSR4) between May 2007 and September 2011, with increasing sensitivity.
In this paper, the method used to reconstruct, in the range 10 Hz-10 kHz, the gravitational wave strain time series $h(t)$ from the detector signals is described. The standard consistency checks of the reconstruction are discussed and used to estimate the systematic uncertainties of the $h(t)$ signal as a function of frequency. Finally, an independent setup, the photon calibrator, is described and used to validate the reconstructed $h(t)$ signal and the associated uncertainties.
The uncertainties of the $h(t)$ time series are estimated to be 8% in amplitude. The uncertainty of the phase of $h(t)$ is 50 mrad at 10 Hz with a frequency dependence following a delay of 8 $μ$s at high frequency. A bias lower than $4\,\mathrm{μs}$ and depending on the sky direction of the GW is also present.
△ Less
Submitted 3 July, 2014; v1 submitted 23 January, 2014;
originally announced January 2014.
-
Probing electron acceleration and X-ray emission in laser-plasma accelerator
Authors:
C. Thaury,
K. Ta Phuoc,
S. Corde,
P. Brijesh,
G. Lambert,
S. P. D. Mangles,
M. S. Bloom,
S. Kneip,
V. Malka
Abstract:
While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam is focused in the gas jet few nanosecond…
▽ More
While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam is focused in the gas jet few nanosecond before the main beam creates the accelerating plasma wave. This second beam is intense enough to ionize the gas and form a density depletion which will locally inhibit the acceleration. The position of the density depletion is scanned along the interaction length to probe the electron injection and acceleration, and the betatron X-ray emission. To illustrate the potential of the method, the variation of the injection position with the plasma density is studied.
△ Less
Submitted 26 September, 2013;
originally announced September 2013.
-
Tuning the electron energy by controlling the density perturbation position in laser plasma accelerators
Authors:
P. Brijesh,
C. Thaury,
K. Ta Phuoc,
S. Corde,
G. Lambert,
V. Malka,
S. P. D. Mangles,
M. Bloom,
S. Kneip
Abstract:
A density perturbation produced in an underdense plasma was used to improve the quality of electron bunches produced in the laser-plasma wakefield acceleration scheme. Quasi-monoenergetic electrons were generated by controlled injection in the longitudinal density gradients of the density perturbation. By tuning the position of the density perturbation along the laser propagation axis, a fine cont…
▽ More
A density perturbation produced in an underdense plasma was used to improve the quality of electron bunches produced in the laser-plasma wakefield acceleration scheme. Quasi-monoenergetic electrons were generated by controlled injection in the longitudinal density gradients of the density perturbation. By tuning the position of the density perturbation along the laser propagation axis, a fine control of the electron energy from a mean value of 60 MeV to 120 MeV has been demonstrated with a relative energy-spread of 15 +/- 3.6%, divergence of 4 +/- 0.8 mrad and charge of 6 +/- 1.8 pC.
△ Less
Submitted 19 October, 2012; v1 submitted 5 January, 2012;
originally announced January 2012.
-
The self-injection threshold in self-guided laser wakefield accelerators
Authors:
Stuart P. D. Mangles,
Guillaume Genoud,
Michael S. Bloom,
Matthias Burza,
Zulfikar Najmudin,
Anders Persson,
Kristoffer Svensson,
Alexander G. R. Thomas,
Claes-Goran Wahlstrom
Abstract:
A laser pulse traveling through a plasma can excite large amplitude plasma waves that can be used to accelerate relativistic electron beams in a very short distance---a technique called laser wakefield acceleration. Many wakefield acceleration experiments rely on the process of wavebreaking, or self-injection, to inject electrons into the wave, while other injection techniques rely on operation wi…
▽ More
A laser pulse traveling through a plasma can excite large amplitude plasma waves that can be used to accelerate relativistic electron beams in a very short distance---a technique called laser wakefield acceleration. Many wakefield acceleration experiments rely on the process of wavebreaking, or self-injection, to inject electrons into the wave, while other injection techniques rely on operation without self-injection. We present an experimental study into the parameters, including the pulse energy, focal spot quality and pulse power, that determine whether or not a wakefield accelerator will self-inject. By taking into account the processes of self-focusing and pulse compression we are able to extend a previously described theoretical model, where the minimum bubble size required for trapping is not constant but varies slowly with density and find excellent agreement with this model.
△ Less
Submitted 5 January, 2012;
originally announced January 2012.
-
Non-invasive characterization of transverse beam emittance of electrons from a laser-plasma wakefield accelerator in the bubble regime using betatron x-ray radiation
Authors:
S. Kneip,
C. McGuffey,
J. L. Martins,
M. S. Bloom,
V. Chvykov,
F. Dollar,
R. Fonseca,
S. Jolly,
G. Kalintchenko,
K. Krushelnick,
A. Maksimchuk,
S. P. D. Mangles,
Z. Najmudin,
C. A. J. Palmer,
K. Ta Phuoc,
W. Schumaker,
L. O. Silva,
J. Vieira,
V. Yanovsky,
A. G. R. Thomas
Abstract:
We propose and use a technique to measure the transverse emittance of a laser-wakefield accelerated beam of relativistic electrons. The technique is based on the simultaneous measurements of the electron beam divergence given by $v_{\perp}/v_{\parallel}$, the measured longitudinal spectrum $γ_\parallel$ and the transverse electron bunch size in the bubble $r_{\perp}$. The latter is obtained via th…
▽ More
We propose and use a technique to measure the transverse emittance of a laser-wakefield accelerated beam of relativistic electrons. The technique is based on the simultaneous measurements of the electron beam divergence given by $v_{\perp}/v_{\parallel}$, the measured longitudinal spectrum $γ_\parallel$ and the transverse electron bunch size in the bubble $r_{\perp}$. The latter is obtained via the measurement of the source size of the x-rays emitted by the accelerating electron bunch in the bubble. We measure a \textit{normalised} RMS beam transverse emittance $<0.5$ $π$ mm$\:$mrad as an upper limit for a spatially gaussian, spectrally quasi-monoenergetic electron beam with 230 MeV energy in agreement with numerical modeling and analytic theory in the bubble regime.
△ Less
Submitted 27 May, 2011;
originally announced May 2011.
-
X-ray phase contrast imaging of biological specimens with tabletop synchrotron radiation
Authors:
S. Kneip,
C. McGuffey,
F. Dollar,
M. S. Bloom,
V. Chvykov,
G. Kalintchenko,
K. Krushelnick,
A. Maksimchuk,
S. P. D. Mangles,
T. Matsuoka,
Z. Najmudin,
C. A. J. Palmer,
J. Schreiber,
W. Schumaker,
A. G. R. Thomas,
V. Yanovsky
Abstract:
Since their discovery in 1896, x-rays have had a profound impact on science, medicine and technology. Here we show that the x-rays from a novel tabletop source of bright coherent synchrotron radiation can be applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
Since their discovery in 1896, x-rays have had a profound impact on science, medicine and technology. Here we show that the x-rays from a novel tabletop source of bright coherent synchrotron radiation can be applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
△ Less
Submitted 12 May, 2011;
originally announced May 2011.
-
Calibration and sensitivity of the Virgo detector during its second science run
Authors:
The Virgo Collaboration,
T. Accadia,
F. Acernese,
F. Antonucci,
P. Astone,
G. Ballardin,
F. Barone,
M. Barsuglia,
A. Basti,
Th. S. Bauer,
M. G. Beker,
A. Belletoile,
S. Birindelli,
M. Bitossi,
M. A. Bizouard,
M. Blom,
F. Bondu,
L. Bonelli,
R. Bonnand,
V. Boschi,
L. Bosi,
B. Bouhou,
S. Braccini,
C. Bradaschia,
A. Brillet
, et al. (153 additional authors not shown)
Abstract:
The Virgo detector is a kilometer-length interferometer for gravitational wave detection located near Pisa (Italy). During its second science run (VSR2) in 2009, six months of data were accumulated with a sensitivity close to its design. In this paper, the methods used to determine the parameters for sensitivity estimation and gravitational wave reconstruction are described. The main quantities to…
▽ More
The Virgo detector is a kilometer-length interferometer for gravitational wave detection located near Pisa (Italy). During its second science run (VSR2) in 2009, six months of data were accumulated with a sensitivity close to its design. In this paper, the methods used to determine the parameters for sensitivity estimation and gravitational wave reconstruction are described. The main quantities to be calibrated are the frequency response of the mirror actuation and the sensing of the output power. Focus is also put on their absolute timing. The monitoring of the calibration data as well as the parameter estimation with independent techniques are discussed to provide an estimation of the calibration uncertainties. Finally, the estimation of the Virgo sensitivity in the frequency-domain is described and typical sensitivities measured during VSR2 are shown.
△ Less
Submitted 18 January, 2011; v1 submitted 27 September, 2010;
originally announced September 2010.